Improvement in furnaces for roasting ores



UNITE STATES PATENT OFFICE.

NATHAN BARTLETT, OF CENTREVILLE, NEW JERSEY, ASSIGNOR TO HIMSELF ANDFRANKLIN OSGOOD, OF RICHMOND COUNTY, NEV YORK.

IMPROVEMENT IN FURNACES FOR ROASTING CRES-" Specification forming partof Letters Patent No. 77,950, dated May 19, 186B.

To all whom it may concern:

Beit known that I, NATHAN BARTL'ETT, of Centreville, in the State of NewJersey, have invented a new and useful Improvement in the Constructionand Mode of Operating Ovens for Roasting or Desulphurating Orcs; and Ido hereby declare that the following is a full and exact descriptionthereof, reference being had to the accompanying drawings, and to thefigures and letters marked thereon, and in which- Figure 1 is a frontelevation of apair of my improved ovens with their furnaces and chimney;Fig. 2, a top view of' the same; Fig. 3, a vertical transverse sectionof the ovens and one of the furnaces through the line a b in Fig. 2, theleft-hand portion corresponding with a section through the line cdinFig. 4, and the right-hand portion to a section through the line efin the same figure; Fig. 4, a vertical longitudinal section through thecenter of one set of the ove-ns; Fig. 5, a vertical lon gitudinalsection through the' center of one of the furnaces.

In all these gures the same parts are indicated by the same letters ofreference.

The ores of all metals, witha very fewlexceptions, require roasting,either forthe pur-` poseof producing higher oxidation or to expelinjurious admixtures of volatile substances; but 'some oresrequiregreater heat than others to effect the requisite' degree ofcalcination, and

fsome also require a peculiar treatment during the. process. y

For these purposes various forms of kilns 'andoven's have been essayedbutby none of suchplans', far das' I amable to ascertain, can suchaco'ntr'ol *of the operation be secured as will alwaysproduce asatisfactory result. The object and nature of my invention are to effecta more thorough expulsion of those foreign substances that can bedissipatedby the action of heat which are usually combined or associatedwith the metalsin the ores than is accomplished by the present modes ofoperation and treatment, as wellV as' v'to save labor and time and tolessen v`the quantity of fuel usually consumed in the process; also, to'afford such control ofthe operation as will secure the best result ormost desirable degree of' calcination in the various kinds of ore.

To enable others skilled in the art to make and use my invention, I willproceed to describe its construction and operation.

I construct my ovens usually in three seetions-that is, an upper, lower,vand middle section-which are all built between the same verticalplanes, and are connected'together alternately by their ends into acontinuous oven, as shownat A, B, and C, Figsl, 3, 4.

Each section is about fourteen feet long, six feet wide, and two and ahalf feet high. The upper part or roof of leach section is anat orelliptical arch, as shown in Fig. 3. The sides are vertical Vfor abouttwelve inches of' the height, -`'and the bottom or floor is hat. Each.section has an inclination of about ten inches in its length. The uppersection, as shown in Fig. 4, `slopes downward to the front, where itconnects, bymeans of the break or opening D, with the middle section, B.The middle section, B, slopes downwardlfrom this connection to the back,where it connects, by means of thcbreak oropening E, with ,the lowersection, C, and the lower section, C, in like 'ma-nner, slopes downwardto the front. Each section has two semicircular or otherwise shapedopenings, one at either end, for the convenience 'of manipulation andinspection, and which, when not in use for these purposes, should be4closed with doors or Stoppers, as shown at F F F, Fig. 4. f

At the upper back end of the top section A, and communicating with it bythe opening Gr, there is a hopper-shaped funnel, H, constructed ofmasonry, as 'shown in Figs. 1, 2, 3, 4, through which the ore is passedto the upper or first section, A, of the oven.

On one side of the sections or oven I con- -s'truct the furnace K,'Figs.1, 3, 5, and tit it A with grate-barsand ash-pit, asshown. Thisfurnaceconnects with the lower 'end ofthe 'bottom section, C, by meansof' the flue L, Figs. 3, 4, 5, andthe heat and name, -after'filling thissection, pass up vthrough the-breakor 'opening E into the `middlesection, Vand after filling it they" pass up throughthebr'eak or openingD into the top section, A, which,in

like manner, becomes filled with the heat and flame from the furnace,and which, after passing through all the sections of the oven` and`taking with it the gases that have been liberated from the ore, entersthe chimney M through the flue N, Figs. 3, 4, 5.

The ore, being previously pulverized, is introduced to the rst or topsection of the oven through the aperture G in the funnel H. It is thenraked forward, by manipulating through the openings at its ends, till itpasses over and down through the break D into the upper end of themiddle section, B. It is then raked backward, by manipulating throughthe openings in its ends, till it passes over and down through the breakE into the upper end of the lower section, C. The ore should be spreadevenly over the floors of all J[he sections to a proper depth.

All the sections being thus charged with ore, the `iiame and heat fromthe furnace K, entering at the lower end of the bottom section oftheoven, soon ills it andv the upper sections by passing up through thebreaks or openings E and D, and by reverberating the heat downwarduponthe ore spread upon the iloors the whole quantity of ore is evenlyeX- posed to its calcining action.

By ,this arrangement of the sections and their inclined position, themanipulation of the ore is not only greatly facilitated and the draft ofthe furnace promoted by the upward direction of the, current in passingthrough them, but the heat being greatest at the lower end of the bottomsection of the oven and lea-stA at the upper end of the top section,where the ore is introduced, the ore is submitted to a greater heat asthe quantity of volatile matter which it contains is diminished, whichis important, for, in most cases, the liability of the ore to injuryfrom the action of heat in the torrifying process is diminished by theexpulsion of the volatile substances.

During the process of calcination the ore should be frequently stirredor raked, so as to submit every particle of it to the action of theheat, and on that in the lower section being fully roasted ordesulphurated it should be immediately drawn out at the opening in thelower or front end of that section. The ore inthe middle sectionis thento be drawn down through the break or openin g at its lower end into thelower section and spread over its floor, and in like manner the ore fromthe top section is to be drawn down and spread over the floor of themiddle section. The floor of the top section is then to be replenishedand covered with raw ore from the funnel at its top end, and in thismanner the operation is continued, making it a perpetual oven.

The degree of heat in thev oven should bev under immediate control,which may be done 111 various ways, such as by a damper in the chimney,by doors to the ash-pit of the furnace, or by adjustable vents in theend doors ofthe sections.

An oven of three sections, and of the sizes herein given, will calcineor desulphurate about three tons of ore per day of twentyfour hours, asI have practically ascertained. The number of ovens should therefore beproportioned to the quantity of ore required for the daily consumptionof the smelting-furnace.

The whole number of ovens thus required should be built in one block,but in pairs, as shown in the drawings, so as to have two furnaces andtwo sets, of ovens together alternately, thereby retaining andeconomizing the heat as much as possible in the lateral direction of theovens and furnaces, and so that one chimney-stack may answer for eachpair of ovens, and the outer ends of such block of ovens should befortified or secured by means of thick and lheavy abutm ents or walls,so that the weight of the end masses may render lateral bracingunnecessary.

As a means of getting the pulverized ore to the side of the funnels,through which it is fed to the ovens, I construct all along the front ofthe block an elevated roadway or trestle-work, having an incline atveither end for the ascent and descent of the wagons. By this means theore is carted up and deposited on the top or roof of the ovens and inthe immediate vicinity of the funnels, from whence it is convenientlyshoveled into them, as required.

In the construction of these ovens any kind of stone or brick that willwithstand lire or heat may be used, and the form, size, and number ofthe sections may be varied, as parties requiring such ovens may deemexpedient for their purpose or for the kind of ore they are working. Itherefore doy not conne myself to the exact construction herein shown ordescribed, but claim the right, under this patent, so long as theprinciple of my invention is retained, to vary the same as may beconsidered advisable or expedient, in vieur of the nature of the ore orthe circumstances under which the ovens are to be constructed andoperated.

Having thus described the construction and operation of my improvedovens for calcining or desulphurating ores, what I claim therein as myinvention, and desire to secure by Letters Patent, is-

l. The sectional arrangement of the oven and the breaks or openings bywhich the sections are coupled or united together, constructed andoperating substantially as described.

2. The combination of the sectional oven with a furnace and chimney,constructed and operating substantially as described. q

3. A sectional oven, as herein described, in combination with openingsor doors in both ends of each section of such oven, for the pur, posesstated, constructed substantially as dc-V scribed.

4.. Constructing a sectional oven with thc sections alternately inclinedto each other, for the purposes stated', arranged and operatingsubstantially as described.

5. The arrangement and combination with each other in pairs of thesectional ovens,

the'furnaces, and the chimneys, in the manner and for the purposesubstantially as described.`

- NATHAN BARTLETT.

Witnesses:

JOHN COCHRANE, EDWARD LYON, Jr.

